Electric furnace



April 15, 1924. 1,490,732

T. F. CALLAGHAN ELECTRIC FURNACE Filed OCT.. 23, 1918 2 Sheets-Sheet 2 Patented Apr. l5, 1924. v

UNITED -sTATEs 'moans r. CALLAGHAN,

OF CLEVELAND, OHIO, ASSIGNOB T0 E. Gf UI-H'LEIT, OF MIL- WAUKEE, WISCONSIN.

ELMTRIC FUBNACE.

Application iled October 23, 1918. Serial No. 259,346.

To all whom it may conce/m.

Be it known that I, THOMAS F. CAL- LAGHAN, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Electric Furnaces, of which the following is a full, clear, and exact description.

The present invention is directed toward electric furnaces of the resistance type, and provides a construct'on by which the resistance element or elements may be supported within the furnace upon the walls of the furnace.

One object of the invention is to support the resistance element or elements in such manner that the elements may vexpand and contract during heating and cooling periods without inducing undue strains upon the supports for the resistance elements or the walls of the furnace.

A further object is to construct the suports for the resistance elements substantially as parts of the furnace wall, thus eliminating a different rate of expansion between the wall and the supports for the resistance elements. l

' A further object is to carry the supports uponl blocks which form parts of the furnace wall, which blocks may be removed from the wall should the supports become broken or damaged, thereby necessitating repair.

A further object is to provide a protection'adjacent each support to protect the resistance element engaging with each support.

Other objects will appear as description of the invention proceeds, and generally the invention may be said to comprise the elements and combinations thereof set forth in the accompanying claims.

Reference should be had to the accompanying drawings forming a part of this specification, in which- Fig. 1 shows in elevation a portion of a wall of an electric furnace of t e resistance type embodying my invention; Fig. 2 is a Vsection. through a portion of the wall; Fig. 3 is a section through a portion of the wall l nace wall illustrating Fig.

showing the mannerlin which a block embodyinw my invention may be removed; Fig. 4 is a ront elevation of a portion of a furp the manner in which a block may be removed from the wall; and 5v is a perspective view showing an instrument employed in the removal of a plug from a .furnace wall.

Referring ,to the drawings, ticularly Figs. 1 and 2, there is indicated a portion of a wall of an electric furnace. It is not deemed necessary to discuss the general form of construction of the furnace inasmuch as this invention is not concerned with that matter, and any form of furnace to which the invention herein disclosed may be adapted, is considered within the scope of my invention.

The walls of the furnace may be formed of any desired material, and in any desired manner. But, of course, the walls should be constructed of heat resistant material.

In the drawings I have shown the wall as composedof bricks or blocks of heat resistant material, which are set in, and held in place in the usual well known manner. No limitation is intended by the use of blocks, as other forms of lining may be used.

The blocks are generally indicated at 10, these blocks forming the main portion of the wall' of the furnace. At a suitable portion, the wall has incorporated as a part thereof, a series of blocks which are indicated at 11. These blocks are placed side by side and extend throughout the distance or space upon theV furnace wall through which it is desired to have a resistance element or elements extend.

Each block 11 is provided with an extension 12, which extension has a groove 12a in the top thereof, adapted to receive a portion of a resistance ele-ment.

In the present instance, the resistance element which is indicated at 13, is a ribbon cf resistance material such as niehrome, or an equivalent electrical resistance material. Above the exension 12, is a protecting member 14. This member 14' is spaced somewhat from the extension 12 so as to leave an open space which permits of the resistance mateand more parrial being placed over, or removed from the extension 12.

The resistance material 13 as indicated, is preferably in the form of a continuous strip or wire, and it is arranged in a series of loops, the upper ends of the loops being supported by and extending over the projections 12, the lower looped portions being unsupported and unrestrained so far as any fastening is concerned. The purpose of providing the construction which is just described, is to permit the free expansion and contraction of the resistance element. There being no fastening for the lower portions of the loops, there is nothing to prevent the free movement of the resistance material.

In other words, the resistance material may expand and contract independently of the contraction and expansion of its supports or the Wall of the furnace and with substantially no strain in the resistance material, at least, no strains suiiciently great to disrupt the resistance material.

There may be a number of resistance elements mounted within a furnace, and I have shown in Fig. 1, a second resistance element below the one at the upper portion of the drawing. Attention is called to this fact merely to indicate that the free lower loops of the upper resistance element lie between the adjacent blocks 11a on the lower row of blocks, and these loops, it will be noted, lie between the protecting extensions 14. I therefore, one of the loops burns out or otherwise is broken, the protecting member 14 will serve to prevent the upper strip of resistance material from coming in contact with the lower strip of resistance material, which would, of course, cause a short circuit, to which more or less damage is always incident.

Attention is called to the fact that the supports for the resistance element are carried by the wall directly, and that these su ports are in effect integral with the wa l, and of the same, or substantially the same material as the wall, so that there is no problem incident to a difference in the rate of expansion and contraction of the wall and the support or supports fori the resist-ance element.

While I have provided a series of blocks such as 11, for carrying and supporting the electric resistance supporting member, it is apparent that the su ports, such as 12, might carried or forme directl upon the wall of the furnace, if the wa` were formed otherwise than of blocks, or even if the supports 12 were to be removable, it is-not necessary that they should be incorporated as integral parts of blocks, as they may be se arately formed and inco orated in t e blocks. The utility of a. b ook, having the resistance element support formed as a part f, extendin of it, as well as the protecting member 14 formed as a part of the block w1ll be evident from the fact that if it is necessary to make repairs,'due to the breaking of a resistance element support, this may be readily accomplished by removing the block and substituting another.

In order to facilitate removing the block, I have shown a block constructed in a manner which renders the removal of a block from the wall a comparatively simple matter.

The block is provided with a recessed p0rtion 11, in the back thereof, and with an opening 11c which extends from the recess 11b, partly through the block, to a point adjacent the extension 12, which forms the Support for the resistance element. In the event that it is necessary to remove the block the extension 12 may readily be knocked off b a hammer, and the opening 11 exposed' This permits the insertion of any suitable tool, which in co-operation with a jack can be used to break the setting of the block in the wall, and so permit its removal.

As one form of block removing apparatus, attention is directed to that shown in Figs. 3, 4 and 5. In Fig. 5 there is show`n a tool having a shank 15 with a head 16, the head being sli htly off center. This tool may be inserted t rough the openin 11 in the block, as indicated in Fig. 3, the ead 16 within the recess 11b and engaging a wa l thereof. From the part 15 there extends a U-shaped portion 17 which is adapted to extend through openings such as indicated at 18 in the brid e member 19. This brid e member has en feet portions 2O and si e feet portions 21, the feet portions 20 resting upon the portions of the wall above andr below the block to be removed, While the feet 21 engage with portions of blocks which are adjacent the sides of the block to be removed.

As before stated, the 'yoke 17 extends through openings 18, and at the ends of the yoke are provided openings 17". These openings may be aligned with an opening ,in a lever 22, and a pin 23 slipped through the aligned openings which holds these members together and forms a fulcrum for the lever 22. This lever 22 has a head 24' moved from the wall and a new block insert' ed in place thereof. It will at once be apparent that this is a very-convenient con-v struction from the view inttof repair, 1n-

asmuch as the time required Iis comparativeI ducting,

l small, and in the operation of` furnaces of tliis character it is im ortant that the furnace be out of commission as short a time as possible.

It will be understood that in all the foregoing construction which has been discussed, the supports for the resistance material is made of a suitable electrical insulating material.

Having describ d my invention, I claim:

1. In an electric resistance furnace, a furnace wall, supports carried by the wall, said supports being formed of heat resisting material and material substantially the same in character as the wall, and Iresistance material supported by said supports the resistance material being substantially entirely exposed to the interior of the furnace and so disposed that it may contract and expand with respect to its supports substantially without strain.

2. In an electric resistance furnace, a furnace wall said Wall having projections' which are substantially electrically non-conresistance material having limited area contact with each of said projections with intermediate portions of the resistance material substantially and entirely exposed to the interior of the furnace, the arrangement between the resistance material and the projections being such that the resistance material may expand and contract relative to theprojections substantially without strain.

3. In an electric resistance furnace, a'furnace wall, supports carried by the wall upon the interior art thereof, and resistance material entire y supported by the supports and depending therefrom.

4. In an electric resistance heating furnace, a furnace wall, electric resistance material arranged as a series of'loops adjacent the wall, and--v means yengaging and supporting said loops only at the top portions of-the loops.

5. In an electric resistance furnace, a furnace wall, electric resistance material within the furnace and adjacent the wall, and supports for said resistance material which are formed as a part of the wall, the resistance .material being entirely supported by said supports and depending therefrom.

6. In an electric resistance furnace, a furnace wall, a series of supports upon the furnace wall, and a continuous strip of resistance material supported by said supports and having loops which hang between the supports.

7. In an electric resistance furnace, a furnace wall, supports carried by the wall, and resistance material hun in loops over said supports, said loops being free at the portions thereof remote from the supports.

8. In an electric resistance furnace, a fur- /blockbeing provided with a may contract and expand with respect to itssupports substantially without strain.

9. In an electric resistance heating furnace, a furnace wall, supporting means carried kby the furnace wall, electric resistance means arranged as a series of loops adjacent the wall, and engaging said supportingl freedom that relative exmeans with such pansion and contraction between supports and resistance means incurs substantially no strains in the resistance material.

10. In an electric resistance furnace, a'.

furnace wall, a series of blocks formed as a part of the furnace Wall, and electrical resistance material supported by the said support and depending between the said supports.

11. In an electric resistance furnace, a furnace wall, a plurality of blocks forming a part of said wall, a support carried by each of said blocks, and a continuous strip of resistance material which is supported by the said supports and depending in loops between the said supports.

12. In anl electric resistance furnace, a furnace wall, a block forming a part of said furnace wall, a support formed as a part of said block, a protecting member also formed as a part of said block and extending over the support, and l resistance material supported by the said support. v

13. A block adapted to form a portion of an electric resistance furnace lining,I said front extension adapted to sup ort a resistance element, an opening exten ing in part through said block and affording a means for gripping the block to remove it from the wall.

14.-. A block adapted to form a portion of the lining for an electric resistance furnace, said block having an extension which forms a support for anelectrical resistance element, said block being formed witha recess in the rear portion thereof, and an opening from said recess which extends toward the front of the block, the said recess being accessible when the aforesaid projection is removed, for the purpose described.

15An electrical furnace comprising a wall, members having projections laid into said wall, and a resistor element looped on said projections in spaced relation to the Wag and adapted to cover a given area of the wa 16.. An electrical. furnace comprising a wall having me bers built therein and provided with projecting portions, and a resistor element provided with loops and suspended in saced relation to the inner surface of the wa l by passing. said loops over the projections.

17. In an electric lresistance furnace, a

5 furnace Wall, supports Acarried by the wall and resistance material hun in loops over said supports said loops bemg free at the portions thereof remote from the supports whereby freedom for expansion or contra'ction is secured, and said resistance materiel 10 being substantially entirely exposed to the interior of lche furnace.

In testimony whereof, I hereunto allx my signature.

THOMAS F. CALLAGHAN. 

